The Earl shared a photo of an old newspaper clipping that had a photo of his family playing – and it looks like Diana and Charles had a relationship that many siblings could relate to. In the snap, the future Princess of Wales, who was then aged five, was playing in her toy car when her younger brother, who was then aged two, poured sand all over it.
WATCH: Princess Diana wows with her piano skills in unearthed video
The scene was observed by their parents, Lord Althorp and Viscountess Althorp, as well as their two other children, Sarah, 11, and Jane, nine.
"A snapshot of family life in 1966," he captioned the post, before adding a variety of hashtags, including one that perfectly summed up the photo: "#terribletwos."
His followers were thrilled with the photo, with many excited to see the picture of a young Princess Diana, as many lamented: "Diana," alongside heart emojis.
The Earl shared this childhood photo
One said: "The look on Diana's face is priceless. Sweet and indulgent but also 'Oh Charles....'," while a second added: "She asked for a car wash, not a dirt wash! Seriously though, that's a lovely family photo."
A third commented: "Diana not impressed with the sand," and a fourth observed: "Princess Diana's smile looks like [Princess] Charlotte."
Although the Earl frequently shares insights into his home, Althorp Estate, he is more reserved with his family photos, but last week he left fans stunned when he shared a photo of the Queen.
Demonstrating the long connection between the Spencer family and the royals, the black-and-white shot showed the Queen back in 1946 when she was still Princess Elizabeth.
Charles and Princess Diana had a close bond
She wore a smart skirt suit as she walked in front of a row of soldiers, with another soldier accompanying her and a man in a suit behind them.
The photo was shared to social media by a royal fan and re-shared by the Earl, who revealed that the man in the suit was his grandfather, Jack Spencer.
The original caption read: "HRH Princess Elizabeth inspects troops at Northampton's Spencer parade in 1946. HRH is closely followed by The 7th Earl Spencer."
Charles added: "Love this - my grandfather Jack Spencer to the left, in suit. He’d served (and been wounded) in the First World War."
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